Disappearing Water

[gryphon25]

I've noticed recently that the water in the coolant overflow reservoir is always low when I check it. I haven't noticed any leaks and so far there haven't been any warnings from the car.
I am concerned because we are heading into the summer period and I would like to get ahead of this.
Do you guys have any tips or are there any common problems that can cause this issue. My hope is that this can be an easy fix that I can get done myself.

 

[Solo Man]

I recently fixed a water leak on a 1999 E46 328i where the sender unit that is located in the bottom water pipe leading from the bottom of the radiator to the engine, was leaking water. It is a clip in type of sender unit and the O-ring started leaking water. Got a new O-ring from local engineering shop and leak was fixed. Not sure if they still have the sender unit in the bottom hose on the E90/91 cars!

 

[Dewald Basson]

I've noticed recently that the water in the coolant overflow reservoir is always low when I check it. I haven't noticed any leaks and so far there haven't been any warnings from the car.
I am concerned because we are heading into the summer period and I would like to get ahead of this.
Do you guys have any tips or are there any common problems that can cause this issue. My hope is that this can be an easy fix that I can get done myself.

Expansion tank, open her up after driving around and have a look from below.

 

[gryphon25]

Thanks guys.

I'm leaving work early today so that I can get home before dark and have a better look to see if I can find where the leak is.
The car is also due for a service soon so if I don't have any luck I'll have them check it for me

 

[Yuben]

Check the car and breather screw. I had that problem where there was no signs of a leak.

What was happening was that the coolant was escaping while driving more like stream so no signs.

I changed both the cap and screw and the problem went away:coolShake:

 

[Riaad]

On the e90...common fault is the coolant plate, situated right at the back of the engine...you generally dont see any leaks because of the engine heat. But i had this problem, you can maybe check under neat...they might be some residue on the catalytic.

Not sure if this issue is only on the 320i...but here is a tread i found...
http://upgr8s.blogspot.co.za/2012/03/bmw-n42-n46-engine-cover-coolant-leak.html

too much of a speech to attempt this, ended up getting it done at SMG for a reasonable sum.

Hope this helps:coolShake:

 

[osiris]

Or you could take it to a radiator place and get it pressure tested. They will find that leak in a couple minutes.

 

[Dewald Basson]

Or you could take it to a radiator place and get it pressure tested. They will find that leak in a couple minutes.

That is to easy man you have struggle first :roflol:

 

[osiris]

Or you could take it to a radiator place and get it pressure tested. They will find that leak in a couple minutes.

That is to easy man you have struggle first :roflol:

LOL :roflol:

 

[1979papijan]

I've noticed recently that the water in the coolant overflow reservoir is always low when I check it. I haven't noticed any leaks and so far there haven't been any warnings from the car.
I am concerned because we are heading into the summer period and I would like to get ahead of this.
Do you guys have any tips or are there any common problems that can cause this issue. My hope is that this can be an easy fix that I can get done myself.

the is a little pipe that connect on top of the thermostat to the engine block, it is the only pipe that can cause the problem.

 

[JohnLod]

Check the plate as suggested earlier in the post on the back of the cylinder head.

 

[1979papijan]

I've noticed recently that the water in the coolant overflow reservoir is always low when I check it. I haven't noticed any leaks and so far there haven't been any warnings from the car.
I am concerned because we are heading into the summer period and I would like to get ahead of this.
Do you guys have any tips or are there any common problems that can cause this issue. My hope is that this can be an easy fix that I can get done myself.

the is a little pipe that connect on top of the thermostat to the engine block, it is the only pipe that can cause the problem.

 

[bmw69]

Or you could take it to a radiator place and get it pressure tested. They will find that leak in a couple minutes.

+1 on the pressure check

 

[BadBoy23]

that's a difficult one, gudluck

 

[gryphon25]

So I found where the water was leaking.

There's a section coming from the radiator where a rubber pipe connects.
I've highlighted it in the pic attached.
There is a small dimple on the inside of this "pipe" where there seems to be a very tiny hole allowing to water to leak out.

It looks like this is part of the radiator and cant be swapped out :thumbdo:

 

[Loom]

The radiator on my E36 leaked at that "plastic" part and the complete radiator had to be replaced. :thumbdo:

 

[osiris]

This is BMW for you. They have become a toy shop. making all the important components of things that are critical to the engine out of plastic. These are always the types of things that if go wrong can leave you stranded. Its like they are playing a sick joke on us.

I have owned I think 9 BMW's and I have replaced a crucial cooling system component on every single one of them. All the other cars I owned never ever gave me shit with regards to the cooling system or anything for that matter. They make radiators out of metal like an intelligent person would.

BMW you would think are intelligent but they pretty thick when it comes to creating a cooling system. They will make an engine that produced great power and due to this makes massive amounts of heat and then put a plastic sided radiator with a plastic expansion tank that almost always splits along the seam and leaves you stranded. (Wait this is pretty good business sense :thumbs::dunnoanymore::tiptoe::biglol::roflol

I never heard of buying an expansion tank as a preventative measure on any other brand of car lol

 

[gryphon25]

The radiator on my E36 leaked at that "plastic" part and the complete radiator had to be replaced. :thumbdo:

This is what I've come to realise.

I've managed to slow the leaking at least but I guess I should start looking around for a replacement radiator.

:blueCry:

 

[gryphon25]

I decided with summer coming and I didn't want to risk driving with a broken radiator so I had a new one installed.
I also replaced the top radiator hose and the coolant cap because the rubbers were broken.

As soon as that was finished the brake warning came up so I changed those myself.